This invention relates to heavy-duty shears for attachment to the boom structure and hydraulic system of a backhoe or like apparatus and adapted to steel and other metallic structural elements including ships, storage tanks, beams and plate.
Heavy-duty shears are used for cutting into scrap for recycling, metal plates, storage tanks and a variety of structural metal members, such as I-beams, heavy steel pipes, and girders.
Exemplary of a heavy-duty shears designed specifically for cutting metal plates is Smith U.S. Pat. No. 5,197,193. This type of plate-cutting shear comprises an upper and a lower jaw with rectangularly arranged cutting edges, which enable the shear to produce a rectangular scrap coupon. The longitudinal cutting elements of the upper jaw are convexly configured so that their cutting edges maintain a constant cutting angle with respect to the cutting edges of the longitudinal cutting elements of the lower jaw which are rectilinear in configuration.
Although the Smith heavy-duty shears offers many advantages over prior art plate shearing devices, the convexly shaped cutting elements of the upper jaw tend to push the plate away from the closing jaws. This tendency to express the plate from the jaws may become a problem when movement of the plate is not a part of a larger, stationary structure undergoing demolition.
In addition, the convexly shaped cutting elements of The Smith upper jaw are ineffective for handling and processing structural members such as I-beams, heavy steel pipes, and girders. Instead of capturing these members the convexly configured upper jaw tends to express them from the jaws before they can be either grappled or sheared.
Unfortunately, limited purpose, heavy duty shears such as that of Smith are seldom versatile enough to handle effectively both plates and structural members, or to cut up efficiently both plates and structural members causing excess distortion of the cut pieces. Such distortion reduces the value of the scrap because it cannot be packed tightly enough to create a dense heavy load, and it needs to be mixed with denser material at the foundry. Since both plate and structural members are used extensively in large structures such as ships, storage tanks, offshore oil platforms, trailers and airplanes, there is a need for a multi-purpose, heavy duty shears which will effectively handle and efficiently cut both metal plates and structural metal members.
It is an object of the present invention to provide a novel multi-purpose, heavy duty shears for efficiently cutting both metal plates and structural members such as I-beams, pipes, and tanks.
It is also an object to provide such a heavy duty shears for effectively handling and manipulating both metal plates and structural members such as I-beams, and pipes.
Another object is to provide such a heavy duty shears which is readily attached to the boom structure and hydraulic system of a backhoe or similar apparatus for cutting steel or aluminum structures.